Use of NIR Spectroscopy for Food Quality Inspection

Near IR spectroscopic techniques are very useful in evaluating the content of food. This is because 99% of food is made of proteins, carbohydrates, fats and water. NIR provides a means for measuring these components in food. The NIR region contains the absorbance bands mainly due to three chemical bonds which are C-H (as in fats and oils, hydrocarbons), O-H (as in water and alcohol) and N-H (as in Proteins). By measuring the absorption of these chemical bonds which are due to overtones of molecule vibration, one can quantify the amount of the ingredients. Usually, a calibration procedure is needed to relate the absorption spectra to a few samples with a known and varying amount of ingredients. A mathematical relation is then derived which correlates the depth of absorption peaks to the concentration of ingredients. The NIR technique can be applied for food quality inspection in raw and processed meat, dairy products, baked goods, confectionary, grains, oil seeds and beverages.